This invention relates to a self-sealing coke oven door and more particularly to an improved spring adjusting device for a coke oven door which may be quickly and easily adjusted to apply the required force to a flexible sealing member carried by the door. Such adjustments may be made under extreme adverse conditions of fluctuating ambient and operating temperatures during the coking cycle when tar and pitch-like products and coal dust condense on the outer surface of the door.
As is well known in the art to which my invention relates, the ends of a coke oven are equipped with removable refractory-lined coke oven doors. After a coal charge is fully coked and the oven dampered off from the gas main, suitable equipment on both the pusher and coke sides of the coke oven remove the coke oven doors and hold them during the pushing operation. After pushing, the doors are replaced preparatory to recharging the oven. In recent years, various types of self-sealing cast iron coke oven doors have been employed to prevent the escape of volatile products from the coke oven during the approximately 12 to 24 hour coking cycle. Such conventional type doors usually employ a flexible sealing member which carries a continuous sealing edge in position to engage a sealing surface on the cast iron door jamb when the coke doors are replaced after pushing. As disclosed in U.S. Pat. Nos. 2,442,391 and 2,478,215, exposed elongated threaded members have been employed either alone or in combination with a conventional spring loaded plunger device to urge the sealing edge of the sealing member into engagement with the machined surface on the cast iron coke oven door jamb. Such conventional adjusting devices have been found to work satisfactory on doors at ambient temperatures and prior to the doors being placed in operation on the coke oven battery. Once in operation, however, they fail to operate in the proper manner due to the tar and pitch-like products and coal dust being deposited on the exposed threads of the elongated threaded members. Such deposits on the threads freeze the threaded members in place and prevent the operator from adjusting the force applied to the sealing member should a leak develop at this point between the sealing edge and the cast iron door jamb. Also, such conventional adjusting devices are usually constructed from steel and connected to the side of the cast iron door opposite the side thereof carrying the refractory-lined coke oven door plug. When such devices are exposed to operating temperatures ranging from 600.degree. F. to 700.degree. F., the difference in the coefficients of expansion of the steel and cast iron contribute to the improper operation of the adjusting device and in some cases cause the elongated threaded members to freeze in place.
Once the exposed threaded members of such conventional adjusting devices are frozen in place, they are not repaired or replaced until the door is removed from the coke oven and taken to a door repair facility for complete major or minor repairs. However, in recent years federal and local environmental regulatory agencies have set forth regulations which require that only a specific amount of emissions be allowed to escape from each coke oven door during the coking cycle. To keep most conventional coke batteries operating under such regulations requires the coke oven doors to be constantly changed so that frozen adjusting devices may be repaired or replaced. This adds considerable expense to the operation of the battery and in some cases causes batteries which otherwise are fully operational to be shut down prematurely and dismantled completely.
Other conventional adjusting devices for use on self-sealing coke oven doors with which I am familiar are disclosed in U.S. Pat. Nos. 3,990,950 and 4,216,062.